Publication Abstract

Proceedings-DFI/EFFC 11th International Conference on Piling and Deep Foundations, 2014, Stockholm, Sweden, (DFI)

Numerical Analysis of CFA Piles for High-Rise Building of Administrative Centre Lakeside Park in Bratislava
J. Stacho and J. Frankovská, Slovak University of Technology in Bratislava, Slovakia

The use of continuous flight auger (CFA) piles in Slovakia has increased significantly in recent decades. High-rise building of administrative centre Lakeside Park in Bratislava is based on piled-raft foundation. The technology of CFA has been used due to the advantages of this technology in comparison with driven and bored piles in local geotechnical conditions. Piles have been designed in accordance with Eurocode 7. Resistance of piles was calculated by using an analytical calculation model for bored piles according to Slovak technical standard and CFA technology has been taken into account by coefficient equal to 1.1. Settlement of piles was calculated by using a calculation model which is being used in Czech Republic and Slovakia. Two well instrumented static load tests were carried out to verify the pile design. The results of static load tests showed that the design was conservative. The paper presents analysis of numerical modelling of CFA pile and static load tests. Load-settlement curves and load distribution curves over pile shafts are compared. Software Plaxis 2011 has been used for numerical modelling. Hardening soil model allows considering overconsolidation of Tertiary Silts and water pressure in deep sandy lenses. The article also presents the parametric study where the influences of pile-soil interface reduction factor, overconsolidation ratio and material models of soils are analysed. The results of numerical modelling showed that the most appropriate results have been obtained when the interface reduction factor equal 0.9 and real behaviour of groundwater were considered. The conclusion of the paper confirms that mechanical behaviour of the ground can be better understood and determined by using FEM than analytical methods.

 article #1930; publication #100 (IC-2014)